It has been known, up to now, that carbohydrates with antitumor activity are mostly polysaccharides such as lentinan, schizophyllan, and sceroglucan, obtainable from edible fungi or from Chinese traditional herbs. There have been rare reports dealing with the oligosaccharides with immune-enhancing and antitumor activity. An oligosaccahride, α-L-Fuc-(1-2)-β-D-Gal-(1-3)-β-D-GalNAc-(1-3)-α-D-Gal-(1-4)-β-Gal-(1-4)-D-Glu, a hexasaccharide consisting of fucose, galactose, N-acetyl-galactose, and glucose (J. Am. Chem. Soc. 1995, 117, 7840) can be used as an antigen against breast cancer and now is in clinical trials. Lentinan has been shown to have antitumor and immune-enhancing activity. Lentinan does not directly attack the tumor cells, but stimulates the host immune system to destroy the tumor cells. In our previous patent (Jun Ning, Fanzuo Kong, application number of Chinese Patents: 99126224.7), synthesis of core fragments of lentinan was reported. These fragments consisted of β-linkages showing immune-enhancing and antitumor activities (Jun Ning, Fanzuo Kong, application number of Chinese Patents: 00100376.3). Sulfation of branched oligosaccharides can give them additional properties such as anti-inflammatory and anti-infectious etc. There have been reports dealing with anti-inflammation and inhibition of cell metastasis (WO96/33726).
The repeating heptaose unit of lentinan has the following structure:

It is seen from the above structure that all of the linkages in the heptaose are β-linkages.
Different oligosaccharide structures are related to corresponding antigens of different diseases. Synthesis of certain oligosaccharides by known methods is a complex process. Thus far, there have been no reports dealing with the synthesis and use of the heptaose analogues containing α-linkeges.